I usually use method 2 mainly because I mislaid the special tool I had for opening these crimped cassettes. But I hate them and they aren't very environmentally friendly (correction they aren't environmentally friendly at all). I liked the cartridges with the removeable caps as they could be reloaded.
For commercially-loaded film, I've always used method 1 - pop the end cap off with a bottle opener. Ya never know what the light trap might pick up while roaming aound in the bottom of the camera bag. For what I bulk load myself, one end of the plastic cassette simply unscrews. Those cassettes get their light traps cleaned with tape prior to reloading.
[COLOR=SlateGray]"You can't depend on your eyes if your imagination is out of focus." -Mark Twain[/COLOR]
I now use method 2 as it makes it easier to load film in my change bag (my darkroom being more of a very dim room) but i have noticed scratches on some of my recent films. Don't know if it's the camera or method 2. I'm devving a film tonite so i will try method 1 and see how i go.
I pop factory loads with a two sided bottle opener. I also tend to fold and tear off the tail of the film as well. I've had some films come out with adhesive residue which shows as an unfixed pink blotch of goop on TMax films. I'm very leery about sharp objects in my dark bag lest I puncture or cut the fabric by mistake, so I have no scissors, and the sharp end of the bottle opener is blunted with a chunk of rubber tube.
As far as identifying used cassettes, I bend the leader back on itself to show the film as exposed. There's often little time when shooting an event to trim the leader nicely.
Has anyone found a better tape as far as adhesive residue than vinyl electrical tape for sticking film to spools when bulk loading?